According to Chapter 32, why is the grace of a Guru considered essential for spiritual knowledge?

Chapter 32 strongly emphasizes the supreme importance of a Guru's grace for attaining true knowledge. The text makes it clear that even extensive study of the Vedas, Vedangas, and other scriptures is nothing more than 'mere chaff' without the Guru's blessing. The words from Sai Baba's mouth are portrayed as being incredibly powerful, capable of destroying sins and afflictions just as the sight of the Ganga does. As the chapter states, listening to the words from Maharaj Sai's mouth is what allows a devotee to truly see their own Guru, making Guru's grace the indispensable key to spiritual realization.